1. Filed of the Invention
The present invention relates to an image display apparatus for displaying images complying with different types of display schemes.
2. Related Background Art
Conventional image display apparatuses capable of selectively switching to display a television signal of a high-vision scheme and a television signal of an NTSC scheme are an apparatus having a display screen aspect ratio of 9:16 complying with the high-vision scheme and an apparatus having a display screen aspect ratio of 3:4 complying with the NTSC scheme.
In the former apparatus, in order to display a television signal of the NTSC scheme, an actual display screen is located at the central portion of the entire display screen, and both sides of the entire display screen are displayed as blank portions. In the latter apparatus, in order to display a television signal of the high-vision scheme, an actual display screen is located at the central portion of the entire display screen, and the upper and lower portions of the entire screen are displayed as blank portions.
In order to display a television signal of the NTSC scheme in the former apparatus, the normally interlaced NTSC television signal is subjected to interpolation processing, and the interpolated television signal is displayed in the form of a non-interlaced signal. In order to display a high-vision television signal in the latter apparatus, interlaced scanning is performed in only the vertical direction or both the vertical and horizontal directions. In addition, the image is compressed, or the resolution is suppressed, thereby displaying the resultant image.
When an image corresponding to the high-vision television signal is to be displayed on the image display apparatus complying with the NTSC television signal, since interlaced scanning is performed in only the vertical direction or in both the vertical and horizontal directions of the high-vision television signal, an image represented by the input television signal cannot be entirely displayed, or image quality may be greatly degraded.